Rdioactive Decay

Describe the process of Beta - decay, Beta + decay, how they affect protons and mass numbers, what happens during nuclear arrangement, balance nuclear equations!

Stable & Unstable Nuclei

Most atoms are atable, they have no desire to ever change to what they are not and are okay on their own

Unstable Nuclei however, change the arrangement of their subatomic particles to became another atom.

Examples of stable & unstable nuclei

Our body contains a lot of hydrogen and carbon atoms

Hydrogen is a stabel nuclei and therefore has not desire to change into something else

Carbon 12 is also stable

However a small percentage of carbon; Carbon 14 an unstable isotope has an unstable nucleus and therefor changes to become stable by losing or converting a subatomic particle

Radioactive decay is

Completely random, we cannot tell when an indovidual nucleus will decay

What are the 4 types of Radioactive Decay/Nuclear radiation

Alpha, Beta, Gamma and Neutron Decay

Describe the process of Alpha decay

1 - what it is + symbol

An alpha particle is a helium nucleus so its symbol is α (the Greek letter alpha) or ⁴₂He and it contains 2 protons & 2 neutrons

Describe the process of Alpha decay

2 - what types of nuclei undergo alpha decay

The ones that are quite heavy and have a lot of mass, a lot of protons and neutrons

Describe the process of Alpha decay

3 - how does it happen/ what does it do

When a nucles emits an alpha particles ie 2 protons & 2 neutrons

so mass number -4

& atomic number -2

Describe the process of Alpha decay

4 - Represent the decrease in mass and atomic number in an equation

8 4 4

Be → Be + He

4 2 2

Describe the process of Beta- decay

1 - what is it + symbol

a B- particles is a fast moving electron emmited from the nucleus.

Describe the process of Beta- decay

2 - what happens

emits an electron as a NEUTRON turns into a PROTON

Describe the process of Beta- decay

3 - What type of nuclei undergo Beta- decay

Carbon 14 becaes it has 2 extra neutrons

A neutron turns to a proton

the proton and neutron number are now the same

However it has now become positively charged because it has gained a proton therefore an electron(beta - particle) leave the atom.

Describe the process of Beta- decay

4 - Represent the decrease in mass and atomic number in an equation

The mass number stays the same

The atomic number increases by 1

14 14 0

C → C + e

6 7 -1

Describe the process of Beta + decay

1 - What it is & symbol

This is when the nucleus emits a fast moving positron(which has the chare of the proton but mass of the electron).

It is an electron antiparticle

0

e

+1

Describe the process of Beta- decay

2 - What type of nuclei undergo Beta- decay

Oxygen 15

is an isotope that undergoes positron decay

A proton turns into a neutron, emitting a beta + particle

Describe the process of Beta + decay

3 - Represent the decrease in mass and atomic number in an equation

Mass number stays the same

atomic number decreases by 1

Describe the process of Gamma decay

1- What is it

It is an electromagnetic wave

Describe the process of Gamma decay

2 - How does it occur

It occurs when a nucleus is in its excited state and emits a gamma ray moving to a lower energy state

Describe the process of Gamma decay

3 - how does it affect subatomic particles

Since it is a wave and therefore has no charge, it does not affect any on the mass number or atomic number.

What does it take to stop Alpha radiation

A piece of paper outside the body

How far can an alpha particle travel in air

Its range is 5cm in air

How ionising is alpha radiation

It is largely/strongly ionising; they can literally pull electrons from the atoms they belong to. Also becaus alpha particles are heavy, they have a lot of kinetic energy and will therefore be able to bash into tons of atoms before they run out of juice.

What does it take to stop Beta radiation

A thin aheet of aluminium foil

How far can a Beta radiation travel in air

10 cm to few metres

How ionising is Beta raditon

less strongly ionising; since they have a lower mass than alpha; less kinetic energy snd half the charge of alpha particles

What stops gamma radiation

Absorbed by thick sheet of lead

How far does gamma radiation travel in air

An extremely long range in air

How ionising is gamma radiation

weakly ionising; even though they have no charge

What device allows us to investigate the range in errors of alpha beta and particles and gamma rays

A GM tube (Geiger Muller tube) is a radiation detector

How do we go about understanding calculating range in error

When alpha beta or gamma rays enter the tube it causes an ionization event which is then represented as a count

The ratemeter connected to the tube tells up how many counts per second

There is always background radiation around us and so therefore the tube always has a background count without a sourcepresent

when a source is placed in front of the GM tube the counts per second on the ratemeter will increase massively indicating presence of a higher level of radiation

When we slowly move the GM tube away from the source, the point at which the count rate falls back to the background count is the range in error of particles

gamma rays spead out quickly as;

they move away from eachother

All nucler radiation particles can

ionise the atoms in the materials they are passing through

what are the charges of particeles

Alpha +

Bate -

Describe the process of Neutrom emission less commonly called neutron decay

It is a rare but dangerous emission

Involves the emission of a single neutron from an unstable nucleus

For example, Helium 5 with 2 protons & 3 neutrons decays into the most common form of helium atom, Helium 4

By emitting a neutron, the mass number decreases by 1

atomic numbers stay the same

1

n

0

Because neutrons have no charge, they are highly penetrating

They can cause stable atoms to become radioactive and then decay, releasing ionising radiation